Our present invention relates to a drum-type dyeing machine for the dyeing textiles or other fabric workpieces. More particularly, the invention relates to a drum-type fabric dyeing machine in which the dyeing liquor or solution is supplied to the drum through a perforated pipe and in which the interior of the drum is subdivided by partitions into segments. The invention also relates to a drum for such a dyeing machine.
A drum-type fabric dyeing machine is described, for example in German Patent DE 44 09575 C1. Such a dyeing machine can include a machine housing, a drum rotatable about a preferably horizontal axis in the machine housing, a closable filling opening for the drum and the aforementioned pipe provided with holes and referred to herein as a perforated pipe, which runs coaxial with the axis and serves to introduce the dyeing liquor or solution to the drum.
A dyeing liquor outlet is provided from the space surrounding the drum and the interior of the drum can be provided with partition walls which are connected to the pipe and subdivide the interior of the drum into the segments.
Drum type dyeing machines of this kind are widely used and the interior of the drum can be subdivided, for example, by three equipspaced partitions into segments. The partitions as well as the drum wall are perforated or provided with holes so that the dyeing liquor, introduced centrally into the drum, can disperse through the textile pieces in the drum and can contact them well with a suitable dyeing effect. The dye liquor can then be discharged through the perforations of the drum and then drawn off and if desired replenished and recycled. Such drum-type dyeing machines are not particularly suitable for sensitive fabrics since such fabrics can hang up on the perforations of the partitions and the outer shell of the drum and hence the fabric can be damaged. In addition, as a result of the capture by the holes of the fabric articles, the dynamic movement of the dyeing liquor is limited or obstructed and hence the dyeing effect can be unsatisfactory.
It is the principal object of the present invention to provide an improved drum-type fabric dyeing machine which can be used effectively even for sensitive fabrics and is less prone to damaging the fabric and to interfering with the dyeing solution dynamics than has hitherto been the case.
Another object of this invention is to provide a dyeing machine which overcomes the drawbacks of earlier fabric dyeing machines of the drum type.
Still another object of the invention is to provide an improved drum for a fabric dyeing machine.
These objects and others which will become apparent hereinafter are attained, in accordance with the invention, by providing the partitions and the drum wall of unperforated material and by forming the connections between the drum walls and the partitions at least on one side of each partition but preferably on both sides of each partition as narrow perforated strips which serve as the dye liquor discharge regions. The term xe2x80x9cperforatedxe2x80x9d and terms of similar meaning are intended to refer to material, e.g. stainless steel sheet, which can be formed with openings of any size and configuration. These can be circular holes, elongated holes, slits or openings of other shapes.
More particularly, a drum-type fabric dyeing machine according to the invention can comprise:
a machine housing;
a dyeing drum rotatable in the housing about an axis and having a closable filling opening for introducing fabric to be dyed into the drum and removing dyed fabric from the drum, the drum having a nonperforated drum wall surrounding the axis;
a pipe provided with a multiplicity of holes extending in the drum along the axis and coaxial with the drum for distributing a dyeing liquor in the drum;
means for collecting dyeing liquor from the drum;
a plurality of radial nonperforated partitions within the drum connected to the pipe and subdividing an interior of the drum into segments; and
perforated strips of widths which are small relative to widths of the partitions interconnecting at least one side of each of the partitions with the drum wall and discharging the dyeing liquor from the drum.
Since the partition and the drum wall or shell are of smooth unperforated material, e.g. stainless steel sheet, damage to fabrics, for textiles introduced into the drum need not be feared. Damage in the region of the perforated pipe forming the solution-inlet unit need not be a problem since rotation of the drum displaces the textile material outwardly so that the fabric will not come into contact with the perforated pipe.
However, to allow the solution to be discharged from the drum, the narrow perforated regions of the steel material are provided. When the drum is rotatable only in one rotation these strips need only be provided on one side of the partition. However, when the drum is oscillated back and forth or rotated in both rotational senses it is found to be advantageous to provide the strips on both sides of the partition. The perforated regions function as solution-discharge regions and, according to the invention there are only limited regions in which the perforations or holes are provided and which could possibly damage the fabric. However, by providing these strips so that they extend inwardly to the respective partitions, the strips interact with the solution to promote a dynamic movement which contributes to preventing the fabric from hanging up on the perforations even though they are limited in number, and the perforated strips in addition promote an effective dynamic flow of the solution out of the drum.
Preferably the perforated strip has a width which is smaller than a third of the drum diameter and still more advantageously is less than a sixth thereof. The perforated strip should be angled radially inwardly from the drum wall or shell so that between the strip and the drum wall an obtuse angle is formed. This has been found to facilitate the runoff of the solution through the perforated region and also ensures a high quality of the dyeing fabric. It is also conceivable to cover the perforated region by overlying diaphragm or shutter strips so that only a narrow gap remain through which only the dyeing liquor can be discharged and thereby protecting the perforated region or the angled region from contact with the fabric behind the gap.
The angled perforated region can include an obtuse angle with the respective partition. Each perforated region can form a radially inwardly projecting channel or corrugation extending parallel to the drum axis and connected to the repsective partition. To avoid damage to the fabric to be dyed, the transitions from the partitions to the perforated regions and from the perforated regions to the drum wall can be radiused or rounded without sharp edges.